Increased thermosensitivity associated with topoisomerase I deletion and promoter mutations inEscherichia coli
Open Access
- 1 September 1999
- journal article
- Published by Oxford University Press (OUP) in FEMS Microbiology Letters
- Vol. 178 (1) , 141-146
- https://doi.org/10.1111/j.1574-6968.1999.tb13770.x
Abstract
An Escherichia coli mutant with three of the promoters for the topoisomerase I gene (topA) deleted, such that only the sigma 32-dependent promoter (P1) remained, had a decreased level of topoisomerase I at 30 degrees C and showed increased thermosensitivity at 52 degrees C. However, it could still develop thermotolerance and had a wild-type level of resistance to 52 degrees C treatment if exposed first to 42 degrees C. This indicated that newly synthesized topoisomerase I from transcription initiated at P1 was important for development of thermotolerance. Two other E. coli mutants lacking topA were > 100 times more sensitive to high temperature than their wild-type isogenic strains.Keywords
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